A lot of brain surgery is done while the patient is conscious. I want you to imagine the sound this would make while it drills through your skull, one twist at a time.
Pretty fucked up, but skulls are hard, and you ain’t gonna get at the meaty insides any other way. When your brain swells, or fluid builds up in the cranium, you either release the pressure, or your eyeballs pop out and you die. I’m not 100% on the eyeball thing.
This one isn’t that old, probably 1950ish.
Trepanation has been practiced for thousands of years, stretching at least as far back as the ancient Egyptians.
via Flickr http://flic.kr/p/oEBBKg